staging: r8188eu: remove unused field list

The field list in struct recv_buf is initialized but not used.
Remove it.

Signed-off-by: Abdun Nihaal <abdun.nihaal@gmail.com>
Link: https://lore.kernel.org/r/558177d9165792a99f6efb439f6f537e13da705b.1646321515.git.abdun.nihaal@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>